Thermoplastic/thermoset grafted composites

ABSTRACT

Disclosed are thermoset/thermoplastic composites that include a thermoset component directly or indirectly bonded to a thermoplastic component via a crosslinked binding layer between the two. The crosslinked binding layer is bonded to the thermoplastic component via epoxy linkages and is either directly or indirectly bonded to the thermoset component via epoxy linkages. The composite can be a laminate and can provide a route for addition of a thermoplastic implant to a thermoset structure.

CROSS REFERENCE TO RELATED APPLICATION

This application claims filing benefit of U.S. Provisional PatentApplication Ser. No. 62/203,663 having a filing date of Aug. 11, 2015,which is incorporated herein by reference in its entirety.

BACKGROUND

Polymers can generally be categorized as either thermoset polymers orthermoplastic polymers. Thermosets include polymers that are highlycrosslinked and while they may exhibit some softening upon heating, theycannot be melted and reformed. While the lack of recyclability ofthermosets is a detraction as is the fact that components formed ofthermoset compositions cannot be welded to other materials, thesecomponents offer excellent physical characteristics includingtemperature and chemical resistance and dimensional stability as well asbeing very cost effective. Thermoplastic polymers exhibit a meltingtemperature and as such are capable of welding and recycling. Inaddition, they can exhibit higher impact resistance than thermosets andcan also be highly resistant to chemical degradation. Unfortunately,thermoplastic polymers, particularly thermoplastic engineering polymers,can be quite expensive.

Composites that can incorporate both thermoplastic compositions andthermoset compositions could provide the desirable characteristics ofboth polymer types while mitigating the less desirable features.Unfortunately, primarily due to the difficulty in adhering thermoplasticcomponents to thermoset components, it has proven very difficult tocombine the two materials in formation of a stable composite structure.While improvements have been made in forming hybridthermoset/thermoplastic composites, for instance through the utilizationof epoxy-based blended polymers, such as toughened epoxies, the abilityto form hybrid composite assemblies by use of thermoplastic zones inthermoset compotes and relatively quick and inexpensive processingtechniques such as fusion bonding, has still not been achieved.

What are needed in the art are methods for formation ofthermoset/thermoplastic composites and composites formed thereby. Forinstance, low cost hybrid thermoset/thermoplastic composites thatexhibit the dimensional stability and resistance of thermosets whileexhibiting the fusion welding capability of thermoplastics would be ofgreat benefit.

SUMMARY

Aspects and advantages of the invention will be set forth in part in thefollowing description, or may be obvious from the description, or may belearned through practice of the invention.

In one embodiment disclosed herein is a method for forming a composite.For instance, a method can include grafting a binding polymer to asurface of a thermoplastic component. The binding polymer can include aplurality of epoxy groups and the grafting can include reaction of afirst portion of the epoxy groups with a reactive functionality at thesurface of the thermoplastic component. For instance, the reactivefunctionality can be a component of a thermoplastic polymer of thecomponent.

The method also includes crosslinking the binding polymer via reactionof a second portion of the epoxy groups thus forming a crosslinkedbinding layer on the surface. In addition, the method includes reactinga third portion of the epoxy groups and thereby directly or indirectlybonding the binding layer to a thermoset component, and in oneembodiment, to reactive functionality of a thermoset polymer of thecomponent.

Also disclosed are composites that can include a thermoplasticcomponent, a thermoset component, and a binding layer between the twocomponents. More specifically, the binding layer is a cross-linked layerthat is bonded to the thermoplastic component via linkage that includesthe reaction product of a first epoxy functionality of the binding layerand is bonded to the thermoset component via linkage that includes thereaction product of a second epoxy functionality of the binding layer.

In one embodiment, the composite can be a laminate structure, forinstance a laminate structure that can be utilized in formation of alarger assembly. In one particular embodiment, a composite can include athermoset section (e.g., a base plate), a hybrid thermoplastic/thermosetsection, and a thermoplastic section (e.g., a thermoplastic implant),thus providing a thermoplastic implant within a thermoset base plate.The thermoplastic section can then be utilized to join the thermosetbase plate to another thermoplastic component or a hybridthermoplastic/thermoset section via fusion welding or the like. In oneembodiment, the bonded materials can be portions of a larger assembly,for instance a shell structure in a transportation application (e.g.,aerospace).

These and other features, aspects and advantages of the presentdisclosure will become better understood with reference to the followingdescription and appended claims.

BRIEF DESCRIPTION OF THE FIGURES

A full and enabling disclosure of the present invention, including thebest mode thereof, directed to one of ordinary skill in the art, is setforth in the specification, which makes reference to the appendedfigures, in which:

FIG. 1 illustrates an epoxy-containing binding layer grafted to athermoplastic component.

FIG. 2 illustrates methods for ‘grafting to’ and ‘grafting from’ abinding layer of a thermoplastic component.

FIG. 3 illustrates a method for directly grafting a thermoset componentto a thermoplastic component via a binding layer via a ‘grafting to’process.

FIG. 4 illustrates a method for indirectly grafting a thermosetcomponent to a thermoplastic component via a binding layer via a‘grafting from’ process.

FIG. 5 illustrates one embodiment of a composite structure that includesa thermoset section, a hybrid thermoset/thermoplastic section, and athermoplastic section at a joint at which the composite structure isfusion bonded to another thermoplastic component.

DETAILED DESCRIPTION

It is to be understood by one of ordinary skill in the art that thepresent discussion is a description of exemplary embodiments only, andis not intended as limiting the broader aspects of the presentdisclosure. Each example is provided by way of explanation of theinvention, not limitation of the invention. In fact, it will be apparentto those skilled in the art that various modifications and variationscan be made in the present invention without departing from the scope orspirit of the invention. For instance, features illustrated or describedas part of one embodiment can be used with another embodiment to yield astill further embodiment. Thus, it is intended that the presentinvention covers such modifications and variations as come within thescope of the appended claims and their equivalents.

The present disclosure is generally directed to composite structuresthat include a thermoset component bonded to a thermoplastic component.As utilized herein, the terms ‘thermoset component’ and ‘thermoplasticcomponent’ generally refer to structures that include a thermosetcomposition or a thermoplastic composition, respectively, at least atthe surface of the structure. The primary polymer of a thermosetcomposition being one or more thermoset polymers and the primary polymerof a thermoplastic composition being one or more thermoplastic polymers.

A composite structure can not only exhibit desirable qualities of bothcomponents such as impact resistance, thermal and chemical resistance,and dimensional stability, but can also be fusion bonded (e.g., welded)to other components via the thermoplastic component. For instance, acomposite structure can be fusion welded to a second component thatincludes a thermoplastic composition at the surface at which theattachment is made.

In one particular embodiment, the composite structure can be a laminatestructure that includes a plurality of stacked layers attached to oneanother. For instance, a laminate structure can include layers of fiberreinforced thermoplastic tapes, tows, sheets, etc. alternating withlayers of fiber reinforced thermoset tapes, tows, sheets, etc. Ofcourse, the present disclosure is not limited to fiber reinforcedlaminate materials and can be beneficially utilized to bond anythermoplastic component to any thermoset component.

A thermoplastic component can include a thermoplastic composition atleast at the surface of the component. While a thermoplastic compositioncan include any thermoplastic polymer or combination thereof, in oneembodiment, the thermoplastic composition can include a high performancethermoplastic polymer that can exhibit high mechanical properties suchas stiffness, toughness, and low creep that make them valuable in themanufacture of structural products like gears, bearings, electronicdevices, and vehicle parts (e.g., automobile and/or aerospaceapplications such as aerospace shell structures). A high performancepolymer employed in the thermoplastic composition is generallysubstantially amorphous or semi-crystalline in nature and has arelatively high glass transition temperature. For example, the glasstransition temperature of the thermoplastic polymer may be about 100° C.or more, in some embodiments about 110° C. or more, in some embodimentsfrom about 120° C. to about 260° C., and in some embodiments, from about130° C. to about 230° C. The glass transition temperature may bedetermined as is well known in the art using differential scanningcalorimetry (“DSC”), such as determined by ISO Test No. 11357. Highperformance thermoplastic polymers as may be included in a thermoplasticcomposition can include, for example, polyarylene sulfides,polyaryletherketones, polyetherimides, polycarbonates, polyamides, etc.,as well as combination of polymers.

By way of example, a polyarylene sulfide may be a polyarylene thioethercontaining repeat units of the following formula:—[(Ar¹)_(n)—X]_(m)—[(Ar²)_(i)—Y]_(j)—[(Ar³)_(k)—Z]_(l)—[(Ar⁴)_(o)—W]_(p)—wherein Ar¹, Ar², Ar³, and Ar⁴ are the same or different and are aryleneunits of 6 to 18 carbon atoms; W, X, Y, and Z are the same or differentand are bivalent linking groups selected from —SO₂—, —S—, —SO—, —CO—,—O—, —COO— or alkylene or alkylidene groups of 1 to 6 carbon atoms andwherein at least one of the linking groups is —S—; and n, m, i, j, k, l,o, and p are independently zero or 1, 2, 3, or 4, subject to the provisothat their sum total is not less than 2. The arylene units Ar¹, Ar²,Ar³, and Ar⁴ may be selectively substituted or unsubstituted.Advantageous arylene systems are phenylene, biphenylene, naphthylene,anthracene and phenanthrene. The polyarylene sulfide typically includesmore than about 30 mol %, more than about 50 mol %, or more than about70 mol % arylene sulfide (—S—) units. In one embodiment the polyarylenesulfide includes at least 85 mol % sulfide linkages attached directly totwo aromatic rings.

In one embodiment, the polyarylene sulfide is a polyphenylene sulfide,defined herein as containing the phenylene sulfide structure—(C₆H₄—S)_(n)—(wherein n is an integer of 1 or more) as a componentthereof. Examples of phenylene groups that can be present in apolyphenylene sulfide resin include p-phenylene, m-phenylene,o-phenylene and substituted phenylene groups (wherein the substituent isan alkyl group preferably having 1 to 5 carbon atoms or a phenyl group),p,p′-diphenylene sulfone, p,p′-biphenylene, p,p′-diphenylene ether,p,p′-diphenylenecarbonyl and naphthalene groups.

Although an arylene sulfide homopolymer constituted of the samerepeating units among the arylene sulfide groups described above may beused, the use of a copolymer constituted of a plurality of repeatingunits different from each other is preferable in some cases with respectto the processability of the resulting composition. For example, acopolymer may be any one constituted of two or more repeating unitsselected from among the arylene sulfide units mentioned above.

A polyarylene sulfide may be linear, semi-linear, or branched. A linearpolyarylene sulfide includes as the main constituting unit the repeatingunit of —(Ar—S)—. In general, a linear polyarylene sulfide may includeabout 80 mol % or more of this repeating unit. A linear polyarylenesulfide may include a small amount of a branching unit or across-linking unit, with the amount of branching or cross-linking unitsgenerally less than about 1 mol % of the total monomer units of thepolyarylene sulfide. A linear polyarylene sulfide polymer may be arandom copolymer or a block copolymer containing the above-mentionedrepeating unit.

Polyaryletherketones are semi-crystalline polymers with a relativelyhigh melting temperature, such as from about 300° C. to about 400° C.The glass transition temperature may be about 100° C. or more, in someembodiments from about 110° C. to about 200° C. The melting and glasstransition temperatures may be determined as is well known in the artusing differential scanning calorimetry (“DSC”), such as determined byISO Test No. 11357.

In one particular embodiment, for example, the polyaryletherketone is ahomopolymer or copolymer containing a repeat unit of the followinggeneral Formula:

wherein,

-   A and B are independently 0 or 1;-   m and r are independently zero or a positive integer, for example    from 0 to 3;-   s and w are independently zero or a positive integer, for example    from 0 to 2;-   E and E′ are independently an oxygen atom or a direct link;-   G is an oxygen atom, a direct link, or —O-Ph-O— where Ph is a phenyl    group; and-   Ar is one of the following moieties (i) to (vi), which is bonded via    one or more of phenyl moieties to adjacent moieties:

Examples of such polymers include polyetheretherketone (“PEEK”) (whereinin Ar is moiety (iv), E and E′ are oxygen atoms, m is 0, w is 1, G is adirect link, s is 0, and A and B are 1); polyetherketone (“PEK”)(wherein E is an oxygen atom, E′ is a direct link, Ar is moiety (i), mis 0, A is 1, B is 0); polyetherketoneketone (“PEKK”) (wherein E is anoxygen atom, Ar is moiety (i), m is 0, E′ is a direct link, A is 1, andB is 0); polyetherketoneetherketoneketone (“PEKEKK”) (wherein Ar ismoiety (i), E and E′ are oxygen atoms, G is a direct link, m is 0, w is1, r is 0, s is 1, and A and B are 1); polyetheretherketoneketone(“PEEKK”) (wherein Ar is moiety (iv), E and E′ are oxygen atoms, G is adirect link, m is 0, w is 0, and s, r, A and B are 1);polyether-diphenyl-ether-ether-diphenyl-ether-phenyl-ketone-phenyl(wherein Ar is moiety (iv), E and E′ are oxygen atoms, m is 1, w is 1, Ais 1, B is 1, r and s are 0, and G is a direct link); as well as blendsand copolymers thereof.

Another suitable type of high performance thermoplastic polymer that maybe employed is a polyetherimide. Generally, polyetherimides aresubstantially amorphous polymers with a relatively high glass transitiontemperature, such as about 150° C. or more, in some embodiments fromabout 180° C. to about 260° C.

Polyetherimides typically have the following general formula:

wherein,

-   V is alkyl, alkenyl, alkynyl, aryl, heteroaryl, cycloalkyl, or    heterocyclyl; and-   R is a substituted or unsubstituted divalent organic radical, such    as aryl (e.g., 1,4-phenylene, 1,3-phenylene, etc.) alkenyl,    heteroaryl, cycloalkyl, or heterocyclyl, or divalent radicals of the    general formula:

in which Q is a divalent radical, such as —C_(y)H_(2y)—, —CO—, —SO₂—,—O—, —S—, etc., and y is an integer of from 1 to 5, and in someembodiments, from 2 to 3.

Polycarbonates encompassed herein include homopolycarbonates,copolycarbonates and copolyestercarbonates and mixtures thereof. In oneembodiment, a polycarbonate can have number average molecular weights ofabout 8,000 to more than 200,000 and an intrinsic viscosity (I.V.) of0.40 to 1.5 dl/g as measured in methylene chloride at 25° C. The glasstransition temperature of polycarbonates can generally range from about145° C. to about 150° C.

Polycarbonates are a known class of high impact resistant thermoplasticresins characterized by optical clarity and high ductility.Polycarbonates can be defined as polymers containing recurring carbonategroups (—O—CO—O—) in the main chain. Aromatic polycarbonates can beutilized in one embodiment. Suitable aromatic polycarbonates can includepolycarbonates made from at least one dihydric phenol and a carbonateprecursor, for example by using an interfacial polymerization process.

Suitable dihydric phenols that may be utilized include compounds withone or more aromatic rings containing two hydroxyl groups, each directlyattached to a carbon atom of an aromatic ring. Examples of suchcompounds include 4,4′-dihydroxybiphenyl,2,2-bis(4-hydroxyphenyl)propane (bisphenol-A),2,2-bis(4-hydroxy-3-methylphenyl)propane,2,2-bis-(3-chloro-4-hydroxyphenyl)-propane,2,2-bis-(3,5-dimethyl-4-hydroxyphenyl)-propane,2,4-bis-(4-hydroxyphenyl)-2-methylbutane,2,4-bis-(3,5-dimethyl-4-hydroxyphenyl)-2-methylbutane,4,4-bis(4-hydroxyphenyl)heptane,bis-(3,5-dimethyl-4-hydroxyphenyl)-methane,1,1-bis-(4-hydroxyphenyl)-cyclohexane,1,1-bis-(3,5-dimethyl-4-hydroxyphenyl)-cyclohexane,2,2-(3,5,3′,5′-tetrachloro-4,4′-dihydroxybiphenyl)propane,2,2-(3,5,3′,5′-tetrabromo-4,4′-dihydroxybiphenyl)propane,(3,3′-dichloro-4,4′-dihydroxyphenyl)methane,bis-(3,5-dimethyl-4-hydroxyphenyl)-sulfone, bis-4-hydroxyphenylsulfone,bis-4-hydroxyphenylsulfide.

The carbonate precursor can be a carbonyl halogenide, a halogen formiateor a carbonate ester. Examples of carbonyl halogenides include carbonylchloride and carbonyl bromide. Examples of suitable halogen formiatesare bis-halogen formiates of dihydric phenols like hydrochinon or ofglycols like ethylene glycol. Examples of suitable carbonate estersinclude biphenyl carbonate, di(chlorophenyl)carbonate,di(bromophenyl)carbonate, di(alkylphenyl)carbonate, phenyltolylcarbonate and mixtures thereof. Although other carbonate precursors maybe used as well, carbonylhalogenides and especially carbonylchloride,better known as phosgene, are preferred.

A thermoplastic composition can include one or more thermoplasticpolymers in conjunction with additives as are generally known in the artincluding, without limitation, impact modifiers, fillers,antimicrobials, lubricants, pigments or other colorants, antioxidants,stabilizers, surfactants, flow promoters, solid solvents, electricallyconductive additives, and other materials added to enhance propertiesand processability. Such optional materials may be employed in thepolymer composition in conventional amounts and according toconventional processing techniques.

In one embodiment, a fibrous filler can be included in the thermoplasticcomposition. A fibrous filler may include one or more fiber typesincluding, without limitation, polymer fibers, glass fibers, carbonfibers, metal fibers, natural fibers such as jute, bamboo, etc., basaltfibers, and so forth, or a combination of fiber types. For instance, thefibers may be chopped fibers, continuous fibers, or fiber rovings.

Fiber sizes can vary as is known in the art. In one embodiment, thefibers can have an initial length of from about 3 mm to about 5 mm. Inanother embodiment, for instance when considering a thermoplastic tapeor tow, the fibers can be continuous fibers. Fiber diameters can varydepending upon the particular fiber used. The fibers, for instance, canhave a diameter of less than about 100 μm, such as less than about 50μm. For instance, the fibers can be chopped or continuous fibers and canhave a fiber diameter of from about 5 μm to about 50 μm, such as fromabout 5 μm to about 15 μm.

As used herein, the term “roving” generally refers to a bundle ofindividual fibers. The fibers contained within the roving can be twistedor can be straight. The number of fibers contained in each roving can beconstant or vary from roving to roving. Typically, a roving containsfrom about 1,000 fibers to about 100,000 individual fibers, and in someembodiments, from about 5,000 to about 50,000 fibers.

As used herein, the term “tow” generally refers to a composite includingcontinuous fibers impregnated in a polymeric composition. For instance,one or more rovings can be embedded in a thermoplastic or a thermosetcomposition to form a tow.

A melt processing device is generally employed to form a thermoplasticcomponent, e.g., a continuous fiber thermoplastic composite, forcombination with a thermoset component. For instance, a single devicecan be used to form the thermoplastic composition and to embed thecontinuous fibers within the thermoplastic composition, although this isnot a requirement, and a thermoplastic composition can first be formed,for instance in an extrusion device as is generally known. Followinginitial formation, the thermoplastic composition, for instance in theform of chips or flakes, can be fed to a device that then embeds thecontinuous fibers within the melted thermoplastic composition. Amongother things, the melt processing device facilitates the ability of thethermoplastic composition to be applied to the entire surface of thefibers and/or fiber rovings.

A thermoplastic composition may be further shaped following formationand prior to addition of a binding layer on the thermoplastic componentthat includes the composition. For instance, a continuous fibercomposite extrudate may be consolidated as with rollers to form acomposite thermoplastic tape.

Formation of a continuous fiber composite is not limited to a meltextrusion pultrusion method, and a continuous fiber composite can beproduced by a number of impregnation methods including, withoutlimitation, emulsion, slurry, fiber commingling, film interleaving, anddry powder techniques. In general, a preferred formation method candepend upon the polymer (e.g., thermoplastic or thermoset) of thecomposition.

For instance, an emulsion process can be used to form a polymercomposite by forming an aqueous emulsion including the polymercomposition having a very small particle size and applying the emulsionto the continuous fibers. For example, the thermoplastic composition canbe milled and combined with a diluent such as water or a water-methanolmixture. A suitable methanol to water mixing ratio can be from 30/70 to50/50 by weight. The continuous fibers can then be soaked in theemulsion and squeezed by means of squeeze rollers, etc. to encouragepickup of the polymer composition by the fibers. The composite can thenbe dried, usually in a hot air drier.

Slurry coating or wet powder processing can be utilized to form acontinuous fiber composite. In slurry coating, a powder including thepolymer composition can be suspended in a liquid medium, generallywater, wherein no solvency exists between the resin and the medium, andthe fiber bundles are drawn through the slurry. The slurry particulatematrix may not wet out the fiber, in which case high pressure can beutilized to consolidate the polymer composition and the fibers into acomposite.

To achieve intimate mixing in emulsion or slurry coating, the particlesize of the slurry or emulsion can generally be smaller than the fiberdiameter.

In fiber commingling, the polymer composition is introduced in fibrousform. Specifically, fibers of the polymer composition and the continuousfibers are mingled as dry blends and wetting of the continuous fibers bya process such as melting thermoplastic composition fibers is carriedout to consolidate the composite. High pressure can also be used duringconsolidation of the continuous fiber composite.

Film casting is another method that can be utilized in forming acontinuous fiber composite. A film casting method can include firstforming a film of the polymer composition. For example, a thermoplasticcomposition can be melt extruded to form a film. The continuous fiberscan then be sandwiched between two films formed of the thermoplasticcomposition. The multi-layer structure can then be melted and calendaredto force the resin into the fibers and form the continuous fibercomposite.

Dry powder coating of continuous fibers is a relatively recent methoddeveloped in continuous fiber composite technology. This method may beadvantageous in certain embodiments as no solvent is required and nohigh stress is introduced in the process. The ultimate goal for almostall powder coating applications is the ability to deposit a thin, eventhickness, high quality coating as efficiently as possible. The polymercomposition can be solid at ambient and elevated storage temperatures,and can be capable of melting to form an adequately low viscositymaterial that can permit flow and to penetrate the fiber tow whenheated.

Regardless of the technique employed, when considering a continuousfiber composite, the continuous carbon fibers are oriented in alongitudinal direction of the composite (the machine direction) toenhance tensile strength. Besides fiber orientation, other aspects ofthe process are also controlled to achieve the desired strength.

A thermoplastic component can be surface modified to include a polymericbinding layer that can be utilized to directly or indirectly bind asurface of a thermoset component in formation of athermoset/thermoplastic composite. While the polymer(s) used to form thebinding layer can comprise multiple different functionalities, thepolymer(s) can include a relatively high concentration of epoxyfunctionality that can be utilized to bind the polymer to thethermoplastic component as well as to crosslink the polymer and bind thepolymer to the thermoset component.

Epoxy is highly reactive and can react with any of carboxy, hydroxy,amino, thiol, or anhydride functional groups under a wide variety ofconditions. As such, the epoxy-containing polymers can be readily bondedto a surface of the thermoplastic component via functionalities that canalready exist on the surface. As such, preprocessing of a thermoplasticcomponent prior to binding of the binding layer will not be required inmany embodiments. For example, a thermoplastic polymer and/or additivesof the thermoplastic composition can be formed or processed to includereactive functionality for reaction with the binding polymer. Forinstance, the surface of a thermoplastic component may be oxidizedthrough any suitable oxidation method including, but not limited to,corona discharge, chemical oxidation, flame treatment, plasma treatment,or UV radiation.

The particular bond formed between the thermoplastic component and theepoxy groups of the polymer can depend upon the functionality on thesurface and as such, the polymer may be bound via covalent bonds,hydrogen bonds, ionic bonds, etc. Though, in general, stronger covalentbonds can be preferred.

The epoxy-containing polymer deposited on the surface can cross-linkfollowing or even during initial deposition. As such, epoxy-containingpolymers can form a permanent or quasi-permanent binding layer on thethermoplastic component. Due to the high concentration of epoxy groupsavailable on the binding polymer, a consolidated, cross-linked bindinglayer that is firmly affixed to a surface of the thermoplastic componentcan be formed with additional reactive epoxy functionality stillremaining in the binding layer following formation. This remaining epoxyfunctionality can provide a relatively simple route for subsequentdirect or indirect binding of the layer to a thermoset component.

In one embodiment, an epoxy-containing binding polymer can be arelatively high molecular weight polymer having a relatively highdensity of epoxy functionality. For example, an epoxy-containing polymerhaving a number average molecular weight of about 2,000 or greater maybe used to form the binding layer. In one embodiment, a binding polymercan have a number average molecular weight of about 100,000 or greater.In general the binding polymer can include an epoxy functionalitydensity of about 10 or more reactive epoxy groups per polymer prior tobinding to the thermoplastic component and crosslinking.

Beneficially, there are a wide variety of epoxy-containing polymershaving a relatively high epoxy density that are suitable for use.Optionally, however, a binding polymer may be preprocessed to provide aparticular epoxy density and/or other desired characteristics.

Generally, any epoxy-containing homopolymer or copolymer possessingabout 10 or more oxyrane rings per polymer can be utilized in forming athermoplastic/thermoset composite. Exemplary binding polymers caninclude, for example and without limitation, epoxidized polybutadiene,epoxidized polyisoprenes, and poly(glycidyl methacrylate) (PGMA), andcombinations thereof. The binding polymer can be a homopolymer or can bea block, graft, alternating, or random copolymer, in which at least oneof the monomer units of the copolymer includes one or more epoxyfunctionalities.

The binding polymer may be applied to a surface of a thermoplasticcomponent according to any suitable methodology. For example, in oneembodiment, a solution may be formed and the thermoplastic component maybe sprayed with or immersed in the polymer-containing solution. In oneembodiment, a fairly dilute solution of the polymer may be formed. Forexample, a solution may contain from about 0.02% to about 0.5% of thepolymer by weight in an organic solvent (e.g., tetrahydrofuran or aketone solvent) and the substrate may be dip-coated in the solution.Aqueous or aqueous/alcoholic solutions are not outside the scope of thepresent invention, though an aqueous-based solution may present certaindifficulties due to the tendency of the epoxy groups to hydrolyze in thepresence of water. For instance, it may be preferable to utilize anaqueous polymer solution fairly soon after formation.

Upon application of the binding polymer to the thermoplastic component(optionally in conjunction with energy addition), a portion of the epoxygroups of the polymer can react with functional groups on the surface.The attachment may involve chemisorption or physisorption of the polymeron the surface, depending upon the materials involved.

FIG. 1 illustrates one embodiment of a binding layer 30 bonded to asurface 14 of a thermoplastic component 12. As shown, a singleepoxy-containing polymer can be grafted to the surface 14 of thesubstrate 12 at multiple points 10 along the length of the polymeraccording to a reaction between the epoxy functionality and reactivefunctionality on the surface 14 of the substrate 12. In this manner, asecure attachment can be formed between the binding polymer and thesurface 14. The binding polymer attached to the surface 14 at multiplerandom points 10 along the length of the polymer can exhibit trains 20(polymer length between bonds), tails 22 (non-bonded polymer ends), andloops 24 (polymer sections looped above the surface 14) that can extendthe height of the polymer above the substrate surface providing a depthto the binding layer 30.

The binding polymer includes epoxy functionality in addition to thatused for attachment of the polymer to the surface. As such, in additionto a portion of the epoxy being utilized for binding the polymer to thesurface, a second portion of the epoxy functionality of the polymer cancross-link the polymer. With reference to FIG. 1, the polymer can formcross-links 32 to self-cross-link a single polymer as well as tocross-link adjacent polymers to each other.

Binding polymers can spontaneously crosslink simultaneous with theattachment reactions as the polymers are bound to the surface oralternatively the binding polymers may be encouraged to crosslinkthrough addition of energy, such as thermal or radiant energy.Combinations of crosslinking protocols may also take place.

According to one exemplary self-crosslinking protocol, attachment of thebinding polymer to the surface through epoxy ring opening can generatehydroxyl groups in the glycidyl fragment. In addition, minor occurrenceof opened epoxy rings can be present on the polymer due to traces ofwater in the environment. At some point, such as during energy additionfor example, these hydroxyl groups can react with another epoxy ring ofthe layer yielding a cross-link having an ether linkage. This can alsogenerate a new hydroxyl group in the polymer that is able to initiatefurther crosslinking.

A binding layer (e.g., a polymer solution used to form a binding layer)can optionally be crosslinked by use of a crosslink agent to furtherencourage crosslinking. In general, a crosslinking agent can be anycompound bearing two or more moieties, at least one of which being ableto react with epoxy ring. For example, ethylene diamine, hydrazine,dicarboxylic acids and the like can be utilized.

Energy may be added to encourage reactions on the surface. For example,the rates of both the crosslinking reactions and the surface attachmentreactions can be increased by heating the surface before, during, and/orafter contact with the binding polymer to a temperature of between about40° C. and about 150° C. For instance, following application of asolution containing the binding polymer to a surface, the surface canthen be heated and held for about 5 minutes at a temperature of about100° C. to promote both the attachment and crosslinking reactions thatcan form the binding layer on the substrate surface.

Following attachment and crosslinking of the binding polymer on asurface, the binding layer can still include an amount of reactiveepoxy, at least a portion of which that be utilized for directly orindirectly binding a thermoset component to the thermoplastic component.For example, from about 10% to about 30% of the epoxy groups on thebinding polymer can react with surface functionalities and formattachment points between the polymer and the surface. Generally, fromabout 10% to about 40% of the epoxy groups on the polymer can beutilized in crosslinking the layer. A third portion of the epoxy groupsof the binding polymer, for instance from about 20% to about 50% in someembodiments, can remain unreacted within the binding layer followingformation of the crosslinked binding layer on the surface and can beavailable for subsequent attachment of the surface to a thermosetcomponent.

This third portion of the epoxy groups of the binding layer can beutilized to bond a thermoset component to the thermoplastic componentaccording to either a ‘grafting to’ process or a ‘grafting from’process. FIG. 2 schematically illustrates examples of ‘grafting to’ and‘grafting from’ processes.

As shown in the left side of FIG. 2, in a ‘grafting to’ process, thecomposite 110 including reactive epoxy groups 16 on the thermoplasticcomponent 12 can be further treated to include additional reactivegroups (e.g., a different type of reactive group, e.g., aldehyde,carboxyl, etc.) that can then be utilized to directly bond with athermoset component 15 and form a thermoplastic/thermoset component withthe bonding layer 18 between the two. In a second embodiment of a‘grafting to’ process the epoxy groups 16 of the pretreatedthermoplastic component 110 can be utilized to directly bond withreactive functionality of the thermoset component 15 and form thethermoset/thermoplastic composite.

FIG. 3 illustrates one embodiment of the present invention in which athermoset component 15 possessing any of several different possiblefunctional groups, e.g., carboxy, anhydride, amino and/or hydroxygroups, on a surface may be directly grafted to a thermoplasticcomponent 12 via the epoxy groups 16 of a binding layer 30 on a surfaceof the thermoplastic component 12. The formed thermoset/thermoplasticcomposite can then include the thermoplastic component 12 tightly bondedto the thermoset component 15 via the binding layer 18 within which mostor all of the epoxy functionalization has been reacted.

Referring again to FIG. 2, in a ‘grafting from’ attachment mechanism, asecondary polymer 19 can be bonded to the thermoplastic component 12 viathe epoxy groups 16 of the thermoplastic composite 110, and thissecondary polymer 19 can include the reactive functionality thatdirectly bonds to a surface reactive functionality of the thermosetcomponent 15. The formed thermoset/thermoplastic composite includes thethermoplastic component 12, the thermoset component 15 and the bindinglayer 18 that, in this ‘grafting from’ embodiment, includes both theoriginal polymer that provided the reactive epoxy and the secondarypolymer 19. As shown, the secondary polymer can be formed on the surfaceof the composite 110 either by polymerization of a monomer, in which themonomer and initiator can be provided in a combined solution, oralternatively in a two-step process in which a polymerization initiatoris first grafted to the epoxy groups and the secondary polymer 19 isthen grafted to the surface via the polymerization initiator.

For example, as illustrated in FIG. 4, a polymerization initiator 32 canbe grafted to the binding layer 30 on a surface of a thermoplasticcomponent 12. Following, a monomer M may then be polymerized on thebinding layer 30. For example, vinyl aromatic monomers, acrylatemonomers or methacrylate monomers can be polymerized on the surface ofthe thermoplastic component via epoxy functionality 16 of the bindinglayer 30. In this embodiment, the secondary polymer 19 may be ‘grown’ onthe binding layer 30 such as through a graft polymerization process. Forinstance, a graft polymerization initiator 32 can be grafted to thebinding layer 30 at epoxy groups 16 as shown. Subsequent contact betweenthe thermoplastic component 12 carrying the polymerization initiator 32and monomer M at reaction conditions can lead to the polymerization ofthe monomer M on the substrate surface via the binding layer 30. Ingeneral, the polymerization initiator 32 can be grafted to the bindinglayer 30 via covalent bond-forming reactions with the epoxy groups 16,though this is not a requirement of the present invention.

Following grafting of the secondary polymer 19 to the binding layer 30,a thermoset component 15 can then be bonded to the thermoplasticcomponent 12 via reaction between reactive functionality of thesecondary polymer 19 and reactive functionality at a surface of thethermoset component 15, thus forming a thermoset/thermoplastic compositethat includes a thermoplastic component 12, a thermoset component 15,and a crosslinked binding layer 18 adhered to both components.

According to one embodiment, a ‘grafting from’ process can be carriedout via Atom Transfer Radical Polymerization (ATRP). According to thisembodiment, following or concurrent with attachment of an initiator to abinding layer, the thermoplastic component can be contacted with themonomer, and polymerization can be initiated from the surface via thebinding layer. Thus, a secondary polymeric layer possessing highgrafting density, for example about 2 chains/nm² or higher, may besynthesized on the surface via the reactive binding layer.

Various polymerization initiators may be utilized in a graftpolymerization process. In one embodiment, an acid may be used such as,for example, bromoacetic acid, which can be grafted to the free epoxygroups of the binding layer at the carboxylic functionality. Otherpolymerization initiators may be alternatively utilized, however. Forinstance, any polymerization initiator displaying carboxy, anhydride,amino, or hydroxy functionality that may graft to the epoxy-containingbinding layer may be utilized. Monomers that may be polymerized on thesurface of the substrate from the polymerization initiator are generallywell known in the art and include, for example, vinyl aromatic compoundsincluding, for example, styrene and 2-vinylpyridine, acrylates, ormethacrylates can be polymerized. In general, any vinyl monomer that maypolymerize by radical polymerization employing the initiator accordingto any known polymerization process as is generally known in the art maybe utilized.

The thermoset component can include a thermoset composition thatincludes one or more thermoset polymers in addition to any additives asare generally known in the art. For example the thermoset compositioncan include a matrix resin selected from one or more of an epoxide, apolyimide, a bis-maleimide, a polyphenol, a polyester, etc., orcombinations thereof that, when fully cured, forms a crosslinkedthermoset matrix.

An epoxy as may be utilized as the matrix resin in a thermosetcomposition may suitably comprise epoxy compounds having more than oneepoxide group per molecule available for reaction. Such epoxyprepolymers include, but are not limited to, polyfunctional ethers ofpolyvalent phenols, for example pyrocatechol; resorcinol; hydroquinone;4,4′-dihydroxydiphenyl methane; 4,4′-dihydroxy-3,3′-dimethyldiphenylmethane; 4,4′-dihydroxydiphenyl dimethyl methane; 4,4′-dihydroxydiphenylmethyl methane; 4,4′-dihydroxydiphenyl cyclohexane;4,4′-dihydroxy-3,3′-dimethyldiphenyl propane; 4,4′-dihydroxydiphenylsulphone; or tris-(4-hydroxyphenyl) methane; polyglycidyl ethers of thechlorination and bromination products of the above-mentioned diphenols;polyglycidyl ethers of novolacs (i.e., reaction products of monohydricor polyhydric phenols with aldehydes, formaldehyde in particular, in thepresence of acid catalysts); polyglycidyl ethers of diphenols obtainedby esterifying 2 moles of the sodium salt of an aromatichydroxycarboxylic acid with 1 mol of a dihalogenoalkane or dihalogendialkyl ether; and polyglycidyl ethers of polyphenols obtained bycondensing phenols and long-chain halogen paraffins containing at least2 halogen atoms.

Other suitable thermoset materials include polyepoxy compounds based onaromatic amines and epichlorohydrin, for example N,N′-diglycidylaniline;N,N′-dimethyl-N,N′-diglycidyl-4,4′-diaminodiphenyl methane;N-diglycidyl-4-aminophenyl glycidyl ether;N,N,N,N′-tetraglycidyl-4,4′-diaminodiphenyl methane; andN,N,N′,N′-tetraglycidyl-1,3-propylene bis-4-aminobenzoate.

Glycidyl esters and/or epoxycyclohexyl esters or aromatic, aliphatic andcycloaliphatic polycarboxylic acids, for example phthalic aciddiglycidyl ester and adipic ester diglycidyl and glycidyl esters ofreaction products of 1 mol of an aromatic or cycloaliphatic dicarboxylicacid anhydride and ½ mol of a diol or 1/n mol of a polyol with nhydroxyl groups, or hexahydrophthalic acid diglycidyl esters, optionallysubstituted by methyl groups, are also suitable.

Glycidyl ethers of polyhydric alcohols, for example of 1,4-butanediol;1,4-butenediol; glycerol; 1,1,1-trimethylol propane; pentaerythritol andpolyethylene glycols may also be used. Triglycidyl isocyanurate; andpolyglycidyl thioethers of polyvalent thiols, for example of bismercaptomethylbenzene; and diglycidyltrimethylene sulphone, are alsosuitable.

An epoxy resin composition can also include a curing agent for the epoxyresin. Such curing agents are well known to those skilled in the art,and include, without limitation diamines, including, but not limited to,diaminodiphenyl sulphone, diaminodiphenyl methane, phenylenediamine,etc.

Thermoset polyimides can include those prepared according to thepractice in which intermediate polyamide acids are first synthesized.Generally these polyamide acids are of two types, high molecular weightand end-capped low molecular weight.

Condensation type aryl polyimides are also encompassed herein. Suchpolyimides can, in one embodiment, be produced by reacting an aryldianhydride and an aryl diamine in an aprotic solvent. Initial reactionproduces a polyamide acid through chain extension.

Methods for producing high molecular weight polyimides without thenecessity of forming polyamide acids are also known. For example, U.S.Pat. No. 3,528,950 (incorporated herein by reference) describes a methodin which a low molecular weight prepolymer is prepared by reacting apoly-functional amine, a poly-functional anhydride, and an end-cappingmono-anhydride of the formula:

where R represents hydrogen or a lower alkyl, by refluxing for a periodof 18 hours.

Such treatment yields two polyimide prepolymers, one of a highermolecular weight and a second of a lower molecular weight, which aresubsequently blended in dry-powder form. The blend of prepolymer canthen be heated to a temperature of 200° C. to 350° C. to form polyimidemacro-molecules.

In yet another embodiment, macromolecular aryl polyimides can besynthesized from a mixture including at least one ester oftetracarboxylic acids, one or more diamines that include a divalent arylradical, and one or more mono- or dialkyl esters of dicarboxylic acids.

The esters of the tetracarboxylic acid may be readily prepared accordingto the known methods from the corresponding dianhydrides. Representativeof the many dianhydrides which may be employed include pyromelliticdianhydride, 3,3′, 4,4′-benzophenone tetracarboxylic dianhydride,2,3,6,7-naphthalene tetracarboxylic dianhydride, 1,2,5,6-naphthalenetetracarboxylic dianhydride, 2,2′,3,3′-diphenyl tetracarboxylicdianhydride, bis (3,4-dicarboxphenyl) sulfone dianhydride,1,4,5,8-naphthalene tetracarboxylic dianhydride.

Representative diamines include benzidine, 4,4′-methylenedianiline,4,4′-diaminodiphenyl sulfone, m-phenylenediamine, p-phenylenediamine.

The mono- or dialkyl esters of the dicarboxylic acid may be preparedreadily from the corresponding anhydride. Representative of anhydridesinclude maleic anhydride, citraconic anhydride,5-norbornene-2,3-dicarboxylic anhydride,methyl-5-norbornene-2,3-dicarboxylic anhydride.

An organic solvent can employed to dissolve the esters and diamine. Thesolvent is one of which does not react with the amines or esters duringthe processing conditions. Representative examples of suitable solventsare N,N-dimethylformamide, N,N-dimethylacetamide, dimethyl sulfoxide,N-methylpyrrolidone, aliphatic alcohols, aliphatic alcohol-ethers, andalkylbenzenes such as xylene. Mixtures of two or more of such solventsmay be employed.

Bis maleimide resins as are known in the art can be employed as thethermoset matrix resin. For instance, suitable bis maleimide resins caninclude those based on the following monomers:

wherein the isomeric species are meta, meta; meta, para or para, para;andX=—CH₂—, —O—, —S—, or

A thermoset composition can include additives as are generally known inthe art. For instance, curing agents, impact modifiers, fillers, dyes,pigments, plasticizers, curing catalysts and other such conventionaladditives and processing aids may be added to the thermosetting resincompositions described herein before curing to influence the propertiesof the final resin composite. Additives in a thermoset composition caninclude thermoplastic materials such as found in toughened epoxies thatcan incorporated thermoplastic impact modifiers incorporated in thethermoset matrix as well as other additives as are generally known inthe art.

In one particular embodiment, the thermoset composition can include afibrous additive, and in particular a continuous fiber additive in theform of rovings such as discussed previously impregnated in thethermoset composition. The thermoset tow thus formed can be combinedwith the surface modified thermoset component and, upon final cure ofthe thermoset resin, can be strongly adhered to the thermoset componentto form the thermoset/thermoplastic composite. By way of example, anuncured or partially cured thermoset composition can be formed byimpregnating continuous fibers in the form of fiber rovings in thethermoset composition to form thermoset composite tapes according tofiber placement and fiber steering methods as are known in the art. Inone embodiment, a fiber placement and fiber steering method can beutilized to form the thermoset component simultaneously with combiningthe thermoset component with the surface modified thermoplasticcomponent.

Briefly, in a fiber placement process, narrow (e.g., about 0.125 in.)tows of resin impregnated fiber can be drawn under tension across a toolof the geometry by a computer controlled head. This head can be capableof delivering up to approximately thirty adjacent tows simultaneously,allowing for high production rates. The narrow tows provide precisecontrol over fiber orientation and, since each tow can be controlledindependently, thickness tapers on complex geometry can be readilyproduced.

A system can provide for adds and cuts (i.e., the start and stop ofindividual tows) to be controlled by a computer via a CAD interface. Forinstance, a plurality of feed paths can be employed in a single layer ofa composite structure to form a predetermined curve of a final product.In forming a complex shape, the feed rate of each tow can beindividually controlled, allowing the longer path of certain tows of asteered radius to feed faster than the shorter path tows.

The ability to support differential tow feed rates combined with theability to add and drop individual tows provides the opportunity toplace fibers along a relatively tight radius with no degradation incomponent quality. In addition, the capability allows for theinterleaving of tows of different polymeric compositions. In particular,a method can be utilized to combine tows of a partially or uncuredthermoset composition with surface modified tows of a thermoplasticcomposition in forming a composite as described herein. Tows ofdifferent compositions can be combined within an individual layer, asalternating individual layers, in a pattern of layer compositions (e.g.,one or more thermoplastic layers between each thermoset layer), or anycombination thereof.

Fiber steering is generally carried out by local compaction duringplacement of the fibers, with each of the impregnated tows having enoughtack to overcome any sliding forces. Fiber steering offers potentialweight savings by overcoming the restriction of discrete linear fiberorientations commonly associated with traditional composites while thefiber placement process allows tailoring of the composite structurewithin a ply level by placing composite tows along curvilinear paths.The combined capabilities provide for optimized structuralconfigurations by tailoring fiber paths within a ply to load paths ofthe component as well as for combining thermoset compositions with thesurface modified thermoplastic components.

Of course, fiber placement and fiber steering technologies are notrequired in formation of a thermoset/thermoplastic composite, and otherknown methodologies can be utilized. By way of example, a thermosetcomponent can be formed and/or combined with a surface modifiedthermoplastic component according to a hand layup process, an openmolding process, a resin infusion process, resin transfer molding (e.g.,vacuum-assisted resin transfer molding), reaction injection molding,resin film infusion, compression molding, centrifugal casting, and soforth.

Following formation of the thermoset component and combination of thepartially or uncured thermoset component with the thermoplasticcomponent, final cure of the thermoset component can be carried out,which can complete formation of the thermoset structure and bind thethermoset composition to the thermoplastic component via reactionbetween reactive functionality of a component of the thermosetcomposition (generally though not limited to reactive functionality ofthe thermoset polymer itself) and reactive functionality of the bindinglayer.

FIG. 5 illustrates one embodiment of a structure 200 that includes alaminate thermoset/thermoplastic composite 210 welded to a thermoplasticcomponent 212. The thermoset/thermoplastic composite 210 includessections 202 of a laminate comprising multiple individual layers, eachof which can include a thermoset composition. Thus, these portions ofthe composite can be referred to as thermoset sections of a structure.

The composite 210 also includes a hybrid sections 204 that include thethermoset layers (e.g., tapes) combined with the surface modifiedthermoplastic layers. A hybrid section 204 can be formed, for example,as described above according to fiber placement and fiber steeringmethods in which thermoplastic tows can be added and thermoset tows canbe cut within and among layers and multiple layers can be combined toform the hybrid laminate sections 204. As the thermoset tows are cut atan end of a hybrid section 204, a thermoplastic section 206 can remainthat forms a thermoplastic implant within the thermoset sheet or tape.

The thermoplastic implant can be utilized in one embodiment as a jointlocation. For instance, the thermoplastic section 206 can be joined withanother thermoplastic component 212 at a welded joint 208.

A thermoset/thermoplastic composite can include materials in addition toa thermoplastic component and thermoset component, as desired. Forinstance, a composite can include metal inserts, a honeycomb core, afoam core, an outer coating, etc.

The thermoset/thermoplastic composites can be used in one embodiment intransportation applications. For example, the ability to provide athermoset structure with a thermoset implant useful for joining to asecond component can be of great benefit is aerospace and aeronauticapplication. For instance, a thermoset/thermoplastic composite can beutilized in forming a stiffened skin panel that can be directly weldedto thermoplastic stiffeners via the thermoplastic implant according toautomated stiffened shell production and assembly techniques for highlyloaded fiber-reinforced, thin walled structures useful in transportationapplications, among others.

This written description uses examples to disclose the invention,including the best mode, and also to enable any person skilled in theart to practice the invention, including making and using any devices orsystems and performing any incorporated methods. The patentable scope ofthe invention is defined by the claims, and may include other examplesthat occur to those skilled in the art. Such other examples are intendedto be within the scope of the claims if they include structural elementsthat do not differ from the literal language of the claims, or if theyinclude equivalent structural elements with insubstantial differencesfrom the literal languages of the claims.

What is claimed is:
 1. A method for forming a composite comprising:grafting a binding polymer to a first surface of a thermoplasticcomponent, the thermoplastic component comprising a thermoplasticcomposition at the first surface, the binding polymer including aplurality of epoxy groups, the grafting including reaction of a firstportion of the plurality of epoxy groups with a reactive functionalityat the first surface of the thermoplastic component; crosslinking thebinding polymer via reaction of a second portion of the plurality ofepoxy groups to form a crosslinked binding layer; and directly orindirectly binding a second surface of a thermoset component to thecrosslinked binding layer, the thermoset component comprising athermoset composition at the second surface, the second surface beingdirectly or indirectly bonded to the crosslinked binding layer viareaction of a third portion of the plurality of epoxy groups.
 2. Themethod of claim 1, wherein the thermoplastic composition comprises ahigh performance thermoplastic polymer.
 3. The method of claim 2,wherein the high performance thermoplastic polymer comprises apolyarylene sulfide, a polyaryletherketone, a polyetherimide, apolycarbonate, a polyimide, or a combination thereof.
 4. The method ofclaim 1, the method further comprising forming the thermoplasticcomponent.
 5. The method of claim 1, wherein the thermoplastic componentis a continuous fiber tape or tow.
 6. The method of claim 1, furthercomprising surface treating the thermoplastic component at the firstsurface prior to grafting the binding polymer to the first surface. 7.The method of claim 1, the binding polymer having a number averagemolecular weight of about 2,000 or greater.
 8. The method of claim 1,the binding polymer including an epoxy density of about 10 or more epoxygroups per binding polymer.
 9. The method of claim 1, wherein thebinding polymer comprises an epoxidized polybutadiene, an epoxidizedpolyisoprene, poly(glycidyl methacrylate) or a combination thereof. 10.The method of claim 1, wherein the crosslinking occurs spontaneously inconjunction with reaction of the first portion of the plurality of epoxygroups.
 11. The method of claim 1, the crosslinking comprising additionof energy to the binding polymer.
 12. The method of claim 1, wherein thesecond surface is indirectly bonded to the crosslinked binding layer,the method further comprising reacting the third portion of theplurality of epoxy groups with one or more additional reactive groups.13. The method of claim 12, wherein the additional reactive groups arecomponents of a secondary polymer grafted to the binding layer.
 14. Themethod of claim 1, wherein the thermoset composition comprises anuncured or partially cured epoxy, a polyimide, a bis-maleimide, apolyphenol, a polyester, or a combination thereof.
 15. The method ofclaim 1, wherein the thermoset component is a continuous fiber tape or atow.
 16. The method of claim 1, further comprising locating thethermoset component adjacent to the crosslinked binding layer accordingto a fiber placement and/or fiber steering process.
 17. The method ofclaim 1, further comprising fusion welding a second thermoplasticcomponent to the composite.
 18. The method of claim 1, furthercomprising locating a thermoplastic implant adjacent to the composite.19. The method of claim 18, further comprising locating the compositebetween the thermoplastic implant and a thermoset section.
 20. Themethod of claim 19, further comprising fusion welding a secondthermoplastic component to the thermoplastic implant.